Decided to start a fresh tracker item for this patch since I already 
attempted to close bug 754449 once before and I want to make 
sure the two fixes stay separate.

Someone emailed me a program whose testing suite could reliably 
reproduce the problem as reported in the bug report (for a quck 
refresher, basically if someone leaves a threading.Thread instance 
running while the interpreter is being shutdown and an exception is 
raised in the thread then that exception will cause  *another* 
exception in the subsequent attempt to report the exception from 
the thread because all globals have been set to None at that point).  
The previous fix that I checked in turned out not to be thorough 
enough (still needed, though).  I am currently waiting for the 
person who emailed me the triggering code to let me know if I can 
publish how to cause the error.

Attached is a patch to remove all instances of accessing globals 
(just as if I was writing a __del__ method for threading.Thread) by 
storing copies of sys.stderr, sys.exc_info, and sys.tracebacklimit.  
All of this is so that a decent approximation of a traceback print-
out can occur without having to call the 'traceback' module since its 
functions depend a lot on each other.

I mainly need someone else who is more familiar with dealing with 
tracebacks to make sure that I have not done something stupid and 
to make sure this is the best way to handle things.